Image scanners are used as an information input source in order to display information of the information input source such as letters and images as CRT or hard copy. Among others, a handy-type image scanner has been developed and used in these days. The handy-type image scanner is put on an information source such as letters and images to be entered, and manually moved by an operator along the information source to be entered. Entered information is outputted to a computer and processed therein into a desired configuration such as CRT display and hard copy. A more increased demand of handy-type image scanners is expected because they are operated easily, and only a desired part of an information source can be selectively entered.
FIG. 5 is a cross-sectional view of a general arrangement of a handy-type image scanner of this type, and FIG. 6 is a plan view of same while operated. In these drawings, reference numeral 1 denotes a casing of the image scanner. Reference numeral 2 refers to an image sensor, 3 to a lens for focusing information shown in a manuscript 4, 5 to an aperture formed in the bottom plate of the casing 1 to read information, 6 to a roller for detecting the movement distance of the image scanner, 7 to a movement detection sensor such as an encoder connected to the roller 6 to detect the movement amount of the image scanner, 8 to an information primary processing circuit, and 9 to a cord for transmitting primary-processed information signals to a microcomputer or other information processing unit.
In order to read information, using the illustrated device, an operator takes the casing 1 in his hand, and puts it on a desired position of the manuscript 4. Subsequently, he moves the casing 1 in the X-direction in FIG. 6. Responsively, information is entered in the image sensor 2 through the aperture 5 in the bottom plate of the casing 1 and the focusing lens 3. In this case, the image sensor 2 itself also scans the information in the length direction of the aperture 5 (in a right-angled direction with respect to the moving direction of the casing) to input the information. The primary processing circuit 8 is supplied with not only signals from the image sensor 2 but also signals responsive to the movement amount of the image scanner detected by the movement detection sensor 7 via the movement detection roller 6. These signals are primary-processed in the primary processing circuit 8, subsequently outputted to the microcomputer or other information processing unit (not shown) via the cord 9, and finally displayed in the form of CRT display, hard copy or other desired configuration.
While the operator operates the image scanner, he must move the casing 1 accurately linearly along the information source to be entered, i.e. in the X direction in FIG. 6. However, accurately-directed scanning cannot be expected by manual movement. Further, when the information to be entered has a width larger than the dimension of the aperture 5 in the length direction thereof, he must first move the casing 1 linearly, and subsequently shift the casing 1 in a direction across the first direction to repeat another linear movement of the casing 1. In these circumstances, a more accurate image reading operation is expected if the image scanner includes a guide apparatus for guiding the image scanner in two right-angled directions. Such a guide apparatus will be particularly effective in an information input device as disclosed in U.S. application Ser. No. 005,957, filed on Jan. 22, 1987 now abandoned, assigned to the assignee of the present application, which has both functions of image scanner and X-Y input device.
A prior art guide apparatus for this purpose is a T-shaped scale so that longitudinal and transverse movements of the information input device are guided by first guiding the information input device in a first direction along one side of the scale, subsequently moving the scale in a second direction right-angled of the first direction by a desired distance with reference to another side of the scale, and moving again the information input device, following to the scale.
Such a T-shaped scale for guiding an image scanner or other information input device is necessarily a large-scaled guide device which is not readily handled. Particularly, when a manuscript is relatively small, an operator will feel it troublesome to move the scale itself.